Methods of this type, such as the Bottelpack® system, are widely used to produce containers of various shapes, sizes, and for different purposes. In this case, they can also be co-extruded containers. In particular, they can be transparent, flexible containers made of polyethylene or polypropylene. In many cases, the containers are both produced and filled with a sterile filling material, such as pharmaceuticals, and sealed in an aseptic operation in one working step. That method is disclosed in WO 2009/086864 A1.
When such containers are used in medicine, an essential performance characteristic is that the filling material can be removed in a suitable manner. If the filling material is, for example, a liquid that is to be infused, for example, an anesthetic, then it must be ensured that the container contains only a minimal residual volume of air, so that when the liquid is squeezed out by squeezing the flexible container, a highly accurate dosage of the liquid is delivered.